A vehicle warning system has been proposed, in which a detection error is given by a difference between a direction of an object detected by a direction-of-object detection circuit or the like and a direction of line of sight detected by a line-of-sight direction detection apparatus. In this system, the degree of coincidence is calculated based on a relationship between the detection error of the line-of-sight direction detection apparatus and the occurrence frequency of the error, and a warning mode is determined based on the calculated degree of coincidence.
A method of analyzing data of an attentive watching direction of a driver has been proposed. In this method, based on an evaluation criterion defining a location of interest of a driver, an instance of the attentive watching direction is classified as either an inside of the location or an outside of the location.
An inattentive driving detection apparatus has been proposed. In this apparatus, a direction of the line of sight of a driver is detected by a line-of-sight detection sensor using an infrared difference image or the like, and a stationary point and a stationary time are measured. In this apparatus, a driver's line-of-sight position on a rear-view mirror, a side-view mirror, or the like is estimated from the detected line-of-sight data, and the number of times the rear-view mirror or the side-view mirror is looked at for confirmation is counted. In inattentive driving, the number of times the confirmation is performed decreases compared with the normal driving. Thus, the number of times the confirmation is performed is compared with a predetermined threshold value to determine whether inattentive driving is being performed or not, and a warning is issued depending on the determination. The threshold value used in the determination is changed depending on the presence of a vehicle ahead or a driving environment, that is, the threshold value used in the determination is changed properly depending on the driving road.
Descriptions of related techniques may be found, for example, in Japanese Laid-open Patent Publication No. 2010-170189, Japanese National Publication of International Patent Application No. 2009-540459, and Japanese Laid-open Patent Publication No. 08-178712.